What is Object Oriented Programming?

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By Sina Nasiri

Object-oriented programming or OOP is a highly popular programming paradigm. OOP languages, like C++, Java, and Python, are utilized by most developers at some point in their careers. At the core of OOP is the concept of objects, which is what makes the OOP languages powerful and flexible.

If you have little to no idea about OOP, don’t worry, the blog will break down every small and big detail about Object-Oriented Programming Language. Also, you will become familiar with its concepts, principles, and some of the most popular OOP languages that are used extensively.

What Is Object-Oriented Programming?

Object-Oriented Programming or OOPs is a programming paradigm that utilizes the concepts of objects and classes in programming. It is majorly used for the implementation of real-world entities like inheritance, hiding, polymorphism, etc. by creating a software program into simple, reusable pieces of code blueprints (classes).

Various Object Oriented Programming languages help in binding the data and functions together such that any other fraction of code can’t access similar data. Also, OOP differs from procedural programming in various ways. For example, procedural programming is about the procedures of writing and performing operations on the data, while object-oriented programming helps us to create objects that are composed of both data and functions.

Advantages of OOP

Below are some of the key advantages of OOP that you need to know:

  • It breaks down complex code into simple structures.
  • OOP offers code reusability. Allowing programmers to again and again on various projects that too with short development times.
  • Enables class-specific behavior via polymorphism.
  • Comes with easy debugging and simple classes that can be implemented easily.
  • Secures all the crucial information through encapsulation.
  • It reduces the time required for code implementations and also allows to map a better structure of programs.

Object-Oriented Programming Concepts

To start working with OOP, you first need to understand its basic concepts that are discussed as follows:

1. Objects

An object is an abstract data type that includes several properties and methods. In some of the languages, they can be defined as objects and are used for offering a structured approach for programming. It is composed of the following operations:

  • State: Used for displaying the property of objects, it is situated in the attributes of an object.
  • Behavior: Used for representing the responses of one object for all of the other objects.
  • Identity: It provides a unique name to objects and helps them interact with each other.

2. Classes

These are the blueprints or extensible program-code templates through which objects are created. They provide initial values for the state and implementation of behaviors. A parent class that creates other classes is known as a metaclass. Class declarations are composed of the following components:

  • Modifiers: Allows class to have either public or default configuration.
  • Class name: It is the name of the class and its first letter should be capitalized.
  • Superclass (if any): It is the name of the parent class and there can only be one parent.
  • Interfaces (if any): A list that contains all the interfaces that are implemented by the class. There can be several interfaces for a single class.
  • Body: It is the main body of a class that is covered with curly braces { }.

3. Packages

These are the namespaces that are utilized for logically organizing the class and interface. They help in easy management of all the codes that are placed inside any package.

4. Attributes

These are the stored information that is defined in the class template. Every object composed of data is stored in the Attributes field. They also define the state of objects and management in various ways.

5. Interfaces

It is a point of interaction between classes and elements outside it. Every time a class adds an interface, it enables the publishing of behaviors through the same. Following are some of the commonly-used terminology related to interfaces:

  • Super class: Also known as a parent class, they are the ones whose features are inherited by their child classes.
  • Sub class: Often known as an extended class, or child class, they inherit the features of other classes.
  • Reusability: It is a technique that includes the derivation of new classes from existing (somewhat) similar classes instead of creating a completely new class. This enables developers to reuse the existing fields and methods as well.

6. Methods

A method is a set of statements aligned for achieving a specific task and reverting with the desired result. It represents behavior and enables users to reuse the codes instead of writing them again. They’re often used for returning the information regarding the objects and updating the associated data as well.

They should be defined in the class and when the objects get instantiated, they can call all the methods defined in the class. These things also help in the process of debugging and managing specific errors instead of working on the whole program. Typically, methods are composed of the following components:

  • Access modifier: States the access points of the applications. Following are the four major types of access specifiers.
  1. Public: Accessible in all classes within an application.
  2. Protected: Allows applications to get accessed from the package, it is defined along with its subclass.
  3. Private: Can only be accessed from the class in which it’s defined.
  4. Default: Accessible only in the similar class or package into which its class is defined.
  • The return type: It is the data type of the value returned via methods.
  • Parameter list: This list contains all the input parameters along with their data type within the enclosed parentheses. In case of no parameters, they’ll be enclosed in empty parentheses ().
  • Exception list: This contains the list of exceptions you want to specify for your methods.
  • Method body: Enclosed into braces {}, the body contains the code that needs to be executed for performing specific operations.

Advantages of OOP Languages over Procedural Programming Languages

OOP languages have several competitive advantages over procedure-oriented programming languages with the most important being discussed as follows:

  1. It simplifies the process of development and management even if the project size is constantly increasing or already swelled up.
  2. It allows developers to hide data and make it private instead of letting the data become globally available that can be accessed from anywhere
  3. It emphasizes simulating real-world events with a better approach. Therefore, devising effective solutions for real-world problems would be much easier with OOPs.

Four Pillars of Object-Oriented Programming

1. Inheritance

Inheritance enables developers to organize and structure the software easily in a natural way. This allows various classes to inherit features or functionalities from other classes and also allows parent classes to provide attributes and behaviors to the respective child classes. Supporting the reusability feature, inheritance allows developers to reuse the same code configurations again and again.

Therefore, parent classes can be configured with basic features and their functionalities can be extended to child classes along with various additional attributes and features. This also results in simplifying the overall process of programming because instead of recreating structures, again and again, child classes can be used for gaining similar functionalities through a parent class.

2. Encapsulation

It is the method of wrapping all of the crucial information inside objects and only displaying the selected information to the global audience. All the attributes and behaviors are described with the help of codes within classes and every time an object is instantiated from the class, its associated information (object and method) will automatically get encapsulated in the objects.

It hides internal software code implementation inside classes and also hides internal data of objects included. Also, it requires users to add fields as either public or private.

  • Private / Internal interface: Configure any method or property as private only if you want to allow other methods of the same class to access the data.
  • Public / External interface: You can make methods or properties public so that they become accessible from outside the class as well.

This feature increases the security factor and allows users to block unknown access from outside the class and only allows public methods & properties to access and update data. All of the major advantages of using encapsulation are listed below, have a look:

  • Extra security: Outside entries are only allowed through public methods and attributes.
  • Lesser mistakes: Since the access is only available via public methods and attributes, the probability of developers making mistakes accidentally would be less.
  • Secures IP address: Since all of the code will be hidden within the class, they will be secured from outsiders.
  • Support: Allows code to get updates and improvements whenever needed.

Moreover, it improves the collaboration with external developers while programming and sharing information with them. It makes the process possible without exposing the templates, private data, or any other intellectual property.

3. Abstraction

Abstraction utilizes dynamic and high-level tools for accessing complex objects. It is an extension of encapsulation that helps in ensuring high-end security by displaying only specific pieces of data and information. Also, the data can be accessed only through certain methods. This results in lowering down the overall data exposure. Some of the advantages of abstraction are summarized below:

  • It offers simple and high-level user interfaces.
  • Allows easy management of software.
  • Enables the representation of complex things simply.
  • Keep users away from all the complexities and offer an advanced level of security.

4. Polymorphism

Polymorphism helps various types within inheritance to perform different tasks as per the need. Therefore, utilizing them correctly will help parents’ classes to function as their children and vice-versa. Also, classes within a single inheritance chain can be used interchangeably without any errors or manipulations within the code.

In simple words, polymorphism refers to the process of designing objects such that they can share behaviors and also allows users to use similar methods for executing various behaviors in the following two ways:

  1. Method overriding: This is a way of providing dedicated implementations of the method that is already provided by its parent class. It occurs in two classes that have an inheritance relationship
  2. Method overloading: It increases the readability of the program and is implemented within a single class.

Some Popular Object-Oriented Programming Languages

While Simula is credited as the first object-oriented programming language, here are some of the most popular OOP languages:

1. Java

It is a multi-purpose and object-oriented programming language that utilizes classes for designing projects with fewer implementation dependencies. Java is an extremely fast, secure, and reliable programming language used for developing applications.

It is one of the most-used languages all around the globe and can be combined efficiently with various technologies like Node.js for building robust, scalable, portable, and full-fledged applications.

2. JavaScript

It is one of the most dynamic and popular OOP languages that is lightweight and is majorly utilized to create dynamic websites as well as web apps. Its implementation enables better interaction between users and client-side scripts for making complex web pages.

Having object-oriented capabilities, JavaScript also helps in constructing network-centric applications and can also be integrated with Java.

3. Python

This high-level programming language comes with a lot of dynamic semantics and built-in data structures. Its combination with dynamic typing and binding makes it extremely easy for developing applications in no time and also utilizes glue language for connecting existing components.

Python’s simplified syntax not only enhances the readability of code but also reduces the overall development time and cost. Python supports modules and packages, which encourages program modularity and code reuse. Moreover, its interpreter and extensive standard library are available for anyone to use for performing tasks more effectively.

4. C++

C++ is one of the most popular OOP languages that is used for building high-performance applications. C++ is very similar to C and both are compatible with each other and also several programs created on either platform can be compiled by one another without manipulating the source code. It is a well-structured language that comes with the following features:

  • It is a cross-platform language utilized for the creation of high-performance applications.
  • It is a modified version of the C language and supports Object-Oriented Programming and comes with better security
  • It allows better control over system resources.

5. Ruby

Along with being an open-source language, Ruby is a general-purpose and interpreted programming language that is considered a perfect object-oriented programming language. It is majorly used for writing Common Gateway Interface (CGI) scripts and can be incorporated into Hypertext Markup Language (HTML).

In addition, it offers clean and easy syntaxes for enabling developers to complete projects quickly. Its syntax is somewhat similar to other popular languages such as Python and C++.


By utilizing objects and classes in programming, Object-Oriented Programming languages aim at breaking down complex things into simple structures so that they can be implemented easily. This helps developers to use a piece of code at different places with ease.

Understanding all of the major six components, namely, objects, class, packages, attributes, interface, and methods will help developers to work with OOP languages without getting perplexed. Moreover, four of the most integral components of Object-Oriented Programming language are also mentioned above which are essential for understanding how OOP works.

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